I don't understand any reason why they should throw away perfectly good hashes. What is the objection if the test is on a live pool, especially if we can all see it? We know that the machines work, and that a lot of them existed last weekend (10 days ago).
This has been discussed over and over again last year, you are competing with your existing and future customers, driving up difficulty and reducing their profit.
Now, if they would redistribute the BTC 780 they gained this way by donating it to a development project or faucet, I guess it would soften the blow, but the point is Yifu personally said they would not do it and they are not doing it and they will never mine with the equipment.
Obviously Yifu is in NY and has no influence of what his minions are doing in CN, and obviously he also has no idea what they are doing behind his back.